Engraving process



Feb. 21, 1928.

R. N. GETCHES ENGRAVING PROCESS Filed Jan. 8. 1924 gnou/woz Wd@ sPatented Feb. 21,1928.

UNITED STATES 1,659,949 PATENT OFFICE.

RAYMOND N. GETCHES, QF GLEN RIDGE," NEW JERSSEY..

ENGRAVING PROCESS.

Application led A.'I'axmary 8, 1924. Serial. No. 685,056.

My invention relates particularly to engraving of metallic orotherplates or cylinders for use in mechanical prlnting, and is especiallyadapted for use in connection with engraving of copper cylinders or flatplates for use in rotary or flat bed printing presses, wherebyphotogravure prints may be c conomically and quickly produced. Myimproved process is also applicable to the production of line printswhere half tones or medium lights or shadows are not present. It isparticularly applicable to the re roduction of toned pictures andphotograp s having innumerable variations of light and shade or to thereproduction of a composite consisting of combined pictorial and printedmatter where both line and 'type Work are to be reproduced with aphotograph or other pictorial print.

Heretofore, in carrying out the so-called rotogravure process, -theJilollowmg mam steps have been considered necessary. First, a negativephotograph is made on celluloid or glass from pictures and printedmatter to be reproduced, it being necessary to separately photograph thepictures and the line Work or printed matter andpassemble the same bypasting or otherwise attaching to the Celluloid or glass backing;second, from this composite negative a positive photographic print ismade on transparent material, such as Celluloid or glass; third, thepositive so made is printed on the so-called carbon tissue which is agelatine coated paper sensitized with potassium bichromate, or othersimilar sensitizing material. This printing is done by exposure of thecarbon tissue to light, through the usual ruled screen and then throughthe composite positive. This last printing operatipn is known as thecarbon printing process. Fourth, the exposed carbon tissue is appliedwhen wet,

under a rolling or rubbing pressure, called squeegeeing to the surfaceof a copper cylinder so that the gelatine adheres thereto, after whichthe paper backing is removed by treatment with hot water which alsodissolves tlie soluble portions of the gelatine, leaving the insolublebichromated gelatine on the cylinder, and the impressions thustransferred are then etched on the cylinder. Fifth, the type or linework is firstletched by the use of the usual ferrie chloride aftercovering the halt` tone portions with asphaltum. The etched portions'are then Washed and dried and the asphaltum re I moved from the halftone or picture portions. Sixth, the previously etched type or line Workis then covered with asphaltum and the tone pictures etched in a similarmanner but With particular attention to the quality of the `high lightsand shadows, or the process is sometimes reversed and the toned picturesetched first vand the line or type work last. Seventh, theasphaltum-last applied is then removed and the cylinder thoroughlycleaned. It is then ready for the printing operation.'

From the following description of my improved process, read withreference to the accompanying drawings, it will be noted that a numberof the steps in the previous process of producing the engraved cylinderor Vplate are unnecessary and are eliminated with a consequent saving oftime, labor, material and expense.

In the accompanying drawings Fig. 1 indicates the various surfacesproduced in the successive steps of one form of my improved process whenused in the production of a composite line and halftone gravure print;Fig. 2 indicates the successive steps when the screening is introducedat another pointv in the process; and Fig. 3 indicates the successivesteps when the screening is produced only on the plate or cylinder to beengraved.

My improved process may be described as follows: First, the pictorialprint or picture (a) submitted for reproduction is photographed as anegative impression (b) on a photographic film having a paper, Celluloidor other suitable backing, either opaque or transparent, in reduced orenlarged size, ac-

cording to the final reproduction required. I prefer to use for thispurpose the well known bromide paper. The type or line matter (c) isalso photographed on similar paper, (d) or other material, butpreferably having a quality of sensitiveness adapted to give muchgreater contrast than thaty used rfor the picturesv having manyintermediate with the negative impression made thereon. The screeningmay also be otherwise produced as hereafter described.

The line and printed portions and the pictorial portions are thenassembled as a composite negative print (f) on the same backing. Second,this composite negative print is then squeegeed face to face with asheet of f gelatinized and sensitized paper (g) known as carbon tissuesimilar to that used in the previous process above referred to, thebromide negative being Wet with water and the carbon tissue wet with thesensitizing solution when squeegeed together. The sensitizing isaccomplished by immersing the carbon tissue for about three minutes in asolution of bichromate of potash-one ounce, potissium-ferricyanide-oneounce, potassium bromide-one ounce, and water-eighty ounces, and afterdraining for a fraction of a minute, immersing in a solutionv comprisingglacial acetic acid-one quarter of an ounce, ydrochloric acid-onequarter of an ounce, formaldehyde (40%)-tive and one half ounces, andwater-one hundred and ninety ounces. If the screen lines have not beenproduced previously on the composite negative print as above described,the carbon tissue (i) may have the screen lines printed thereon, afterbeing sensitized with a three per cent potassium bichromate solution, bybeing exposed to light through the white line screen (e) which producesthe insoluble gelatine lines on the carbon tissue. It is then dried andagain sensitized as previously described before the composite print islsqueegeed thereon. It is obvious that these operations of printing thescreen lines and the picture respectively on the carbon tissue may bereversed. Third, the carbon tissue after being in contact with thebromide or similar print for fifteen minutes or more, ac-

cording to quality or depth of tone desired,

is stripped away from said bromide or simil lar negative leaving thecarbon tissue (y) with the soluble and insoluble gelatine thereon whichis placed in contact with a copper or metallic cylinder or a flat copperor metallic plate and the backing and the soluble portion of thegelatine removed with hot water as in the oldv recess. Fourth, thecylinder is then etched, (le, c) line work and half tone separately asin theold process or as an' entirety by the use of ferrie chloridewithout the necessity of separate etching of the .type or line matterand the pictorial matter, as required in the former rocess, since thisprocess gives a thickness o gelatine and resist making it possible toobtainrequired results in one etching.

The c linder is then washed and is ready for making the print (VZ, Z),as is usual in the process of rotogravure printing.

As an alternative method of producing the screen lines on the cylinderor plate, apiece of sensitized carbon tissue (m) may be exposed to lightthrough the screen' (e.) as above described, then transferred directl tothe cylinder or plate. (n). .When the acking and the soluble gelatineare removed, the insoluble gelatine lines only remain on the surface ofthe cylinder or plate.

The composite negative print, (o) without screen lines, is thensqueegeed onto another sheet of carbon-tissue (p) and the gelatinethereof transferred to the cylinder or plate (n), and su er-imposed onthe previously applied inso uble screen lines. The insolub e` ortions ofthis layer of gelatine are then was ed away, after which the cylinder orplate (g) is ready for etching and printing (r as efore. 1,

n view of the above description, it will be apparent that' through theuse of my process it becomes necessary only to make a singlephotographic bromide or other print of the matter to be reproduced, thisbeing directly applied to the sensitized carbon tissue and the gelatinetransferred therefrom to the cylinder which is immediately etched afterremoval of the paper backing. All photographic reproduction by exposureto light, except photographing for the first negative print and theformation of the halftone screen lines when the latter are formedseparately, is thereby eliminated. The use of any trans arent sheetmaterial is consequently avoi ed.

Having thus described my invention, I do not wishto be understood asbeing limited to the details of pxrocedure and the specific materialsset fort for various changes may be made by those skilled in the artwithout departing from the spirit and scope of my invention.

What I claim and. Letters Patent is:

1. In theprocess of preparing a photogravure 4printing surface, thesteps which comprise placing a negativeimage of the matter to bereproduced having'dark portions and high lights of different densitiesformed on a film containing chemical substances which are ada ted toproduce corresponding. degrees of insolubility in a sensitizedgelatinous or similar ilm, in direct contact with such a gelatinousiilm, separating said image from said gelatinous film for apredetermined period, transferring the latter to the surface to beetched, removing all soluble portionsof said gelatinous film, andetching said surface in the presence of its remaining insoluble portion.

2. In the process of preparing a photogravure printing surface whichcompr1se the following steps, placing a negative silver .bromide imageof the matter to be re rononame and then transelatine to becomeinsoluble,

to the surface tine to become inso uble, and then transferring saidgelatinous film to the surface to be etched. y

4. In the process of producing a photogravure printin surface, incombination with the formation of tone-screen lines at a suitable pointtherein, the steps which comprise placing a negative formed on silverbromide paper, in mtimate contact with a sensitized gelatinous filmwhereby ortions of said negative cause correspon ing portions ofthegelatine to become insoluble, ,Y

transferring said film to the surface to be etched, removing the solubleportions of the gelatine, and then etching said surface.

5. In the process of producing a photogravure printing surface, invcombination with the formation of tone screen lines at a suitable pointtherein, the steps which ,com-- prise placing a negative formed onsilver bromide paper of the matter to be reproduced, in intimate contactwith a sensitized gelatinous film whereby darker, portions of4 saidnegative cause portions of the gelatine to become correspondinglyinsoluble, transferrin said film to the surface to be etched, removingthe soluble portions of said hn, and then etching said surface.

6. In the process of producing a photogravure printing surface, thesteps which comprise assembliner separate photographic paper negatives,matter to be reproduced, on a common backing to form a compositenegative, said negatives of the pictorial matter having photogravurescreen lines formed thereon land having less contrast than the linenegatives, placing said composite negative in face-to-face intimatecontact with a sensitized gelatinous film for a predetermined timeinterval, whereby certain portions o said film are rendered insoluble,transferring said film to the printing surface, removing the solubleportions of said film and etching said surface.

7. The process of preparing a photogravure printing surface whichcomprises the following steps: placing a photographically producednegative silver image of the matter to be reproduced in intimate contactwith a gelatinous film in the presence of a chromate salt, removing saidgelatinous film and transferring it to a photogravure surface,

o the line and pictorial p f produced in intimate contact with a washingaway all soluble portions of said gelatmous matter, and etching saidsurface.

8. The process of preparing Va photogra- .vure printing surface whichconsists in placing a negative silver image of the matter to bereproduced in intimate contact with a gelatinous-film in the presence ofa chromate salt, whereby portions of said gelatinous film correspondingto said image are rendered insoluble in direct proportion to the amountof silver present, transferring said film to a metal printing surface,washing away all soluble portions of said film, and etching saidsurface.

9. The process of preparing a photogravure print-ing surface whichcomprises the -following steps: placing a photographically producednegative image formed on a silver bromide film, of the matter to bereproduced,

'in intimatelcontact with a sensitized gelatinous film in the presenceof a bi-chromate of an alkali, a ferricyanide ofan alkali, a solublehalid salt of an alkali, and water to cause an insoluble condition incertain portions of said gelatinous film correspondin to said negativeimage, transferring sai elatinous film to a printin surface, removingall soluble portions o film, and etching said surface in the presence ofthe remaining portion of said film.

l0. The process of preparing a photogravure printing surface whichconsists in placing a photographically produced negative image formed ona silver bromide film, of the matter to be reproduced, in intimatecontact with a gelatinous film in the presence of a chromate salt,whereby a chemical action takes place between said silver bromide imageand said chromate salt to cause certain portions of said gelatinous filmto become insoluble in direct proportion to the amount of silver presentin the negative image, transferring said gelatinous film to a previouslyrepared metal surface, Washing away the soluble portions of saidgelatinous film, and etching said surface in the presence of theremaining gelatin.

11.4 The process of producing a photogravure printing surface whichcomprises the following steps: placing a photographically producednegative image formed on a silver photographic paper of the matter to beregelatinous film sensitized with a chromate salt whereby portions ofthe gelatin in contact with said image are rendered insoluble indirect-proportion to the silver present at the points of contact,transferring and placing said gelatinous film in contact with theprinting surface to be engraved, dissolving and removing all solubleportions of said gelatin, and etching said surface in the presence ofthe remaining gelatin.

12. The process of producing a photogravure printing surface whichcomprises the said gelatinous` following-steps: placing aphotographically produced bromide paper negative of the image to bereproduced, in a moistened condltion, in face-to-face intimate contactwith a gelatinous film sensitized and moistened wlth a. solutioncontaining a chromate of salt, c ontinuing said contact forapredetermined time interval whereby portions of said gelatinous film incontact with said image are rendered insoluble in direct proportion tothe silver present, removing said film, transferring and squeegeeing itto the surface to be engraved, washing away all soluble portions -ofsaid film, and etching said surface in the presence of the remaininggelatin.

13. The process of producing a photogravure printing surface whichcomprises the following steps: placing a photographic paper containinw asilver salt, on whicha nega# tive image of the subject'to be reproducedhas been projected and developed, in face to face intimate contact witha gelatinous film sensitized and moistened with a solution containingpotassium bichromate-one part, potassium ferricyanide-one part,potassium bromide-one part, and water 8() parts, continuing said contactfor a predetermined time interval whereby portions of the gelatin filmin contact with the negative image are rendered insoluble in directproportion to the silver present, transferring and squeegeeing said filmto the surface to be engraved, washing away all soluble portions of saidgelatin and etching said surface in the presence of the remaininggelatin.

14. The process of preparing a photogravure printing surface whichconsists in placing a sensitized 'photographic paperwhich has beenphotographically exposed to the matter to be reproduced and developed toproduce a negative image containing reduced silver in intimate contactwith a gelatinous film in the presence of a solution containing achromate salt, whereby portions of said gelatinous film contacting withthe silver image are rendered insoluble in direct pr0 portion to .thesilver present, transferring said film to a metal surface on'which aninsoluble gelatin screen formation has previously been applied,dissolving and Washing away all soluble portions film and etchingsaid'surface in the presence of the remaining gelatin.

15. The process of producing a photogravure printing surface whichcomprises the following steps: placing a negative silver image on aphotographic paper ofthe matter to be reproduced, in intimate contactwith a gelatinous film having an insoluble screen formation thereon,said film being sensitized with a solution containing a chromate saltwhereby the remaining soluble portions 0f said film are renderedinsoluble in direct proportion to the silver present in said image,transferring and placing said film in of said gelatinV contact with theprinting surface to be en. graved, dissolving and removing all solubltlportions of said gelatin, and etching said surface inthe presence of theremaining insoluble gelatin.

16. The process of preparing a photogravure printing surface whichconsists in sensitizinga gelatinous film with a solution containingpotassium bichromate, light printing a half tone screen formation onsaid sensitized film, resensitizing said light printed film with asolution containing potassium bichromate, potassium ferrie anide andpotassium bromide, placing sai film in a/moist condition in intimateface to face contact with a negative image, on silver bromide aper, ofthe matter to be reproduced whereby portions of said film not alreadyrendered vinsoluble bv the light printing of said screen formationthereon are also rendered insoluble in direct proportion to the silverpresent in said image, transferring said film to a metal printingsurface, washing'away all insoluble portions of said film and etchingsril surface in the presence of the remaining 17 The process ofpreparing a photogravure printing surface which consists in lightprinting a photogravure screen formation on a photographic papersensitized with a silver salt, photographing the matter to be reproducedon said screened paper, chemically treating said paper to produce anegative image in reduced silver of the matter to be reproducedsuperimposed on the screen formation, placing said negative image inintimate contact with a gelatinous film in the presence of a solutioncontaining a chromate salt whereby portions of said film contactin withthe silver image are rendered insolu le in direct proportion to thesilver present, transferring said film to a metal printing surface,washing away all soluble portions of said film, and etching said surace.

18. The process of preparing a photogravure printing surface whichconsists in light printing a photogravure screen formation over aphotographic exposure, on` a paper sensitized with a silver salt, of thematter to be reproduced, chemically treating said paper to produce anegative ima e in reduced silver of said matter and said screenformation, placing said negative image in intimate contact with agelatinous film previously sensitized with a solution containing achromate salt whereby portions of said film contacting with the silverimage are rendered insoluble in direct proportion to the silver present,transferring sald film to a metal printing surface. washing away allsoluble portions of said film and etching said surface.

, 19. The process of vure printing surface which consists inplacpreparing a photogra ing a negative hotograph, containino reducedsilver, of t e matter to be reproiuced in intimate Contact with agelatinous film in the presence of a solution containing a chromatesalt, whereby portions of said gelatinous film contacting With thesilver image are rendered insoluble in direct proportion to the silverpresent, removing said lm from saidimage, light printing a photogravurescreen formation on said lm without l0 further sensitizing, transferringsaid film to a metal printing surface, Washing awa all soluble portionsof said film and etc ing said surface.

Dated New York, N. Y., January 7 1924.

RAYMOND N. GETCHES.

